1. Field of the Invention
The present invention relates generally to methods and materials for stripping photoresist layers from substrates employed within microelectronics fabrications. More particularly, the present invention relates to methods and materials for stripping ion implanted photoresist layers from substrates employed within microelectronics fabrications.
2. Description of the Related Art
Integrated circuit microelectronics fabrications are formed from semiconductor substrates within and upon whose surfaces are formed resistors, transistors, diodes and other electrical circuit elements. The electrical circuit elements are connected internally and externally to the semiconductor substrate upon which they are formed through patterned conductor layers which are separated by dielectric layers.
In the process of forming resistors, transistors, diodes and other electrical circuit elements within and upon semiconductor substrates, it is common in the art of integrated circuit microelectronics fabrication to form through ion implantation methods within discrete portions of semiconductor substrates or semiconductor layers formed over semiconductor substrates discrete ion implanted semiconductor regions. Such discrete ion implanted semiconductor regions are typically formed through ion implantation methods which employ patterned photoresist layers as ion implantation mask layers.
While patterned photoresist layers typically serve well as ion implantation mask layers in forming discrete ion implanted semiconductor regions within semiconductor substrates or semiconductor layers employed within integrated circuit microelectronics fabrications, it is often nonetheless found that ion implanted patterned photoresist layers which have been employed as ion implantation mask layers are difficult to subsequently strip from semiconductor substrates or semiconductor layers through oxygen plasma stripping methods which are conventionally employed in stripping photoresist layers from substrate layers within microelectronics fabrications such as integrated circuit microelectronics fabrications. The difficulty in stripping such ion implanted patterned photoresist layers employing conventional oxygen plasma stripping methods presumably derives from oxidation of implanted dopant species within the ion implanted patterned photoresist layers. In order to remove those presumably oxidized implanted dopant species along with the ion implanted patterned photoresist layers, there is often conventionally employed within integrated circuit microelectronics fabrications either high power oxygen plasma stripping methods or corrosive plasma stripping methods, such as fluorine containing plasma stripping methods, which often damage the substrate layers from which are stripped the ion implanted patterned photoresist layers. Damage to substrate layers incident to stripping from those substrate layers ion implanted patterned photoresist layers is undesirable within microelectronics fabrications, such as but not limted to integrated circuit microelectronics fabrications, since it is often difficult to fabricate within or upon those damaged substrate layers fully functional or reliable microelectronics fabrications.
It is thus towards the goal of removing from substrate layers employed within microelectronics fabrications ion implanted photoresist layers without damaging those substrate layers that the present invention is generally directed.
Various methods have been disclosed in the art of integrated circuit microelectronics fabrication for removing photoresist layers from substrate layers. For example, Fujimura et al., in U.S. Pat. No. 4,938,839, describe a method for removing an ion implanted patterned photoresist layer from a semiconductor substrate. The method employs cooling the semiconductor substrate while the ion implanted patterned photoresist layer is stripped from the semiconductor substrate with a plasma of an etchant gas composition comprising oxygen.
In addition, Visser et al., in U.S. Pat. No. 5,310,703, discloses a plasma method for stripping a photoresist layer from upon a silicon oxide layer formed over a semiconductor substrate within an integrated circuit microelectronics fabrication, where there is simultaneously avoided migration of inorganic contaminants from the photoresist layer into the silicon oxide layer. To realize this object, the silicon oxide layer is maintained at a positive bias voltage with respect to a plasma employed within the plasma method.
Finally, Keller, in U.S. Pat. No. 5,346,586, discloses a method for selectively etching a polysilicon gate electrode layer to a gate oxide layer while employing a hard mask patterned with a patterned photoresist layer within an integrated circuit microelectronics fabrication. The method employs an in-situ ozone plasma strip of the patterned photoresist layer from the hard mask layer prior to selectively etching the polysilicon gate electrode layer, in order to provide optimal integrated circuit microelectronics fabrication efficiency.
Desirable in the art are additional methods through which ion implanted patterned photoresist layers may be stripped from substrate layers within microelectronics fabrications such as but not limited to integrated circuit microelectronics fabrications without damaging those substrate layers. It is towards that goal that the present invention is more specifically directed.